Our vision is to reduce the impacts of important perinatal viral infections and (re)emerging infectious diseases, and on infants and children by leadership of a collaborative translational research programme and by capacity building of clinician researchers (as described under Research Supervision and Mentoring), especially in the Asia-Pacific Region. Our affiliations and participation with in the University of Sydney Sydney Emerging Infectious Diseases and Biosecurity Institute (SEIB), and the newly awarded NHMRC Clinical centre for research excellence in Critical infections has enabled the Centre to develop research programs into emerging childhood diseases while at the same time building on our previous strengths of perinatal infections. The Centre for Perinatal Infection laboratory undertakes studies of viral immunopathogenesis using animal models of important viral infections in children, particuarly herpes simplex virus (HSV).

Comparing the effects of HSV cutaneous infection on the migration and function between epidermal and dermal skin gamma delta T cells in vivo

The skin is the largest organ of the body and provides the first line of defence against many infections including HSV, a pathogen of global importance. HSV enters the body through breaks in the skin or mucosa where it first encounters immune effectors within the skin. Understanding the immunological mechanisms that govern protective cutaneous immunity is critical to the development of vaccines, antivirals and topical microbicides. Our laboratory uses a murine model of herpes simplex virus (HSV), to understand the parameters for immune protection against viruses in the skin and to define age-dependant differences in neonatal innate and adaptive antiviral immunity.

T cell receptor γδ cells (γδ T cells)are a minor population of circulating T cells. Although they have been found in increased numbers in tissues during the course of several viral infections including HSV, their precise role remains unknown. A subset of γδ T cells, called dendritic epidermal T cells (DETC) express a unique Vγ5/Vδ1 TCR, and are largely resident in the skin.They are in intimate contact with neighbouring epidermal cells such as keratinocytes and Langerhans cells (dendritic cells of the skin and mucosa). They recognise antigen expressed by damaged keratinocytesand produce cytokines (TNF-a, TGF-b, IL-1, IL-3 and GMCSF), keratinocyte growth factors, (IGF-1, KGF-1),and chemokines.They have been therefore shown to play a role in wound repair.

Recently, we have made the key observations using strains of fluorescently tagged HSV that γδ T cells are infected with HSV shortly after skin infection. HSV infection also significantly reduces the number of bystander DETC in the epidermis. Functional and phenotypic differences have recently been reported between epidermal and dermal γδ T cells in mice.

In this project, we will extend our studies to compare changes in morphology, kinetics of migration and viability of HSV infected and bystander epidermal and dermal γδ T cells in the ear skin after cutaneous HSV infection in mice. Utilising ear skin of adult mice in which skin γδ T cellsare GFP+ (B6.CXCR6) we will visualise the juxtaposition and movement of skin γδ T cells in the epidermis and dermis after acute HSV infection. Confocal microscopy observations will be confirmed by selected immunohisto-chemistry and histological studies.